3D Printed Glass: Who Will Get There First?

3D printed glass, anyone? Several new companies are trying to make it a reality. But are the results convincing? Here’s an overview.

The choice if of 3D printing materials is bigger than ever. We can print with about 50 different types of thermopolymers, close to 300 photopolymers, about 20 different metal powders and a few dozen pastes and hydrogels. The search for 3D printable glass is intensifying. New companies are trying new ways to make 3d printed glass. Who‘s going to get there first?

3D Printed Glass: Just Look, Don’t Touch

Did you ever ask yourself what glass is? Most of what we call glass a heated mixture of lime, soda and silica (which is basically sand). These are all readily available in nature and therefore quite inexpensive. It seems logical, then, that one of the first companies to actually develop a system for 3D printed glass is ExOne. That’s because the German 3D printer manufacturer uses a binder jetting process to 3D print with several powders, including metals and sand. In this process the powder particles are glued together and then sintered in a kiln for post-processing.

Although the result of ExOne’s 3D printed glass is geometrically beautiful, it does have a few drawbacks. The 3D objects come out opaque, fragile and coarse to the touch, thus making it ideal mainly for sculptures and artistic projects. But you wouldn’t want to 3D print a window with it.

Hewlett-Packard’s Results Were Not Convincing

The search for functional 3D printed glass began in 2012, when Hewlett-Packard published a paper on the “3D Printing of Transparent Glass”. This sparked rumors that the company was working on a glass 3D printer. The rumors have not entirely died off, even after the announcement of its new color 3D printing technology — which has nothing to do with glass.

HP analyzed extrusion 3D printing of a glass mixture as well as powder bed 3D printing processes (similar to ExOne’s), which both require post-process firing in a kiln (Warm Glass 3D Printing). The HP team also tried mixing glass with polymeric resins (Cold Glass 3D Printing).

In all cases, though, the early results were mediocre at best in terms of both resolution and transparency.

Micron 3DP Might Break Through the Glass

Israel’s Micron3DP developed a system to extrude molten glass (image: Micron3DP)

An Israeli company called Micron3DP recently announced a breakthrough in the 3D printing of warm glass through an extrusion process. Their system basically works like a very high-temperature filament extrusion 3D printer. It is capable of reaching 850° C to melt soda lime glass into a filament that cools down as it form’s the object’s layers.

Micron3DP’s technology can reach 1.640° C and even melt borosilicate glass. That’s a type of heat-resistant glass which adds boric acid into its composition mix. The downside? Like most paste-based extrusion systems, the resolution and the geometric complexity of the 3D printed objects is limited. There thus effectively making 3D printing not as desirable a choice for manufacturing of final products.

3D Printed Glass: The Reversed Approach

Glass manufacturing student and artist Alex Morrison took a different approach. He used a regular MakerBot 3D printer to build the parts he created in CAD. He then made a rubber mold and created wax replicas. These were then used to create a new plaster and silica mold that he filled with glass nuggets. The entire cast was then fired up for the glass to fuse together and thus create the final object.

This process enabled Morrison to create the unique parts he needed for his glass work. However, it seems clear that this process would be difficult to implement in the production of everyday use products.

The “Almost-Glass” Revolution

3D printing can be used to make highly transparent parts using photopolymer resins (image: Stratasys)

Given the difficulties of 3D printing with actual glass, most 3D printer and consumables manufacturer have been working on glass-like substitutes based on highly transparent polymers. Stratasys, 3D Systems and other manufacturers such as EnvisionTEC and Prodways all offer many highly transparent liquid resins.

These include Stratasys’ RGD720 and VeroClear-RG810, which simulate another transparent thermoplastic called PMMA, or 3D Systems’ Accura ClearVue Free SL7870. EnvisionTEC offers the Clear Guide resin while Prodways developed the PLASTCure Clear 100, and there are as many as 75 transparent resins on the professional 3D printing market.

3D Printed “Glass” For Makers

The next revolution in transparent 3D printing filament is called HD Glass (image: Formfutura)

The same is true of filaments in the desktop 3D printing arena. Transparent products such as T-Glase and colorFabb’s XT have been around for some time. And while PET and PET-G do achieve quite a degree of transparency, consumables reseller FormFutura recently went a step further by announcing its HD Glass filament.

The modified PETG has been deemed food-safe and also easier to print than other transparent thermoplastics. In this case “HD” stands for “heavy duty” and Form Futura claims that their filament is tough and temperature resistant while also allowing 90% of visible light to pass through.

Is this going to be enough to mark the end of Tupperware as we know it? Probably not, but the quest for 3D printed glass has but begun.